ASTM C109 Cube Test – Updated Procedure Based on ASTM C109-24

A recent update to our software introduces changes to the cube testing procedure in order to more closely follow the requirements of ASTM C109-24, specifically regarding the rate of platen movement during the compressive strength test.

ASTM C109-24 Clarification

ASTM C109-24 specifies different control methods for platen movement during two distinct halves of the test:

“Obtain this designated rate of movement of the platen during the first half of the anticipated maximum load and make no adjustment in the rate of movement of the platen in the latter half of the loading especially while the cube is yielding before failure.”

Key Standard Requirements

• Initial Load Phase: Control platen movement to achieve a rate of 200–400 lbf/s.

• Post-Initial Phase: No adjustment shall be made to the rate of movement for the latter half of the test.

Software Behavior (Updated)

With the new software version:

• Control Begins at Start: The machine begins controlling the platen movement rate immediately upon pressing Start Test, targeting the user-defined rate until Preload is reached.

• Fixed Rate After Preload: After reaching Preload, the system calculates the average hydraulic motor speed over the final seconds before Preload. This average speed is then used for the remainder of the test, with no further adjustments, ensuring compliance with ASTM C109-24.

Test Setup Best Practices

To ensure optimal results and standard compliance, follow these guidelines:

1. Set Preload Appropriately:

   • Configure the Preload to be around 50% of the anticipated break load.

   • This ensures enough data is collected for calculating a reliable average pump speed and stabilizes the initial load phase.

2. Jog Advance:

   • Use the Jog Advance button to bring the platen within approximately 1/16" of the specimen.

   • This is critical for proper engagement under the new test mode.

3. Tare the Load:

   • Always tare the load after positioning the platen but before starting the test.

4. Jog Advance to Make Contact
   1. C109-24 states, "Bring the spherically seated block into uniform contact with the surface of the specimen."
   2. By initiating contact, the load rate can be controlled immediately after pressing Start Test, instead of attempting to control the rate while closing the gap between the specimen and the breaking head.